The present invention relates to memory cells, and more particularly to phase change memory devices and device fabrication.
Memory cells are fabricated in a variety of ways using a large variety of substances. Depending on the material used in the memory cell, the memory cell may be volatile or non-volatile. Volatile memory loses its stored information when there is no applied current or voltage, while non-volatile memory generally retains information without an applied current or voltage. One kind of non-volatile memory is known as phase change memory. Phase change memory cells are often fabricated using phase change materials that have more than one crystalline state, such as chalcogenides or other materials.
In phase change memory, the programming performance may be dominated by how fast the phase change material can be converted from the amorphous phase (RESET state) to the crystalline phase (SET state). The programming operation which converts the high resistance amorphous phase to the low resistance crystalline phase is referred to as the SET operation. Furthermore, the retention of the amorphous phase is governed by the phase change material's ability to avoid unintentional re-crystallization.